The socket documentation (https://docs.python.org/3/library/socket.html#socket-families) does not list '' as a way to bind to all interfaces for the AF_INET/AF_INET6 address family.

This is answered on SO here: https://stackoverflow.com/a/8034146 but it took me a while to find it. Ideally if this was mentioned in the docs, that would be great.

It's kinda mentioned:

"For IPv4 addresses, two special forms are accepted instead of a host address: the empty string represents INADDR_ANY"

Though it could be more explicit on what means since binding to all interfaces is a common use case.

@ammar2

I see that now. Yeah it's further down in the docs and doesn't actually call out '' like is done for AF_CAN:

A tuple (interface, ) is used for the AF_CAN address family, where interface is a string representing a network interface name like 'can0'. The network interface name '' can be used to receive packets from all network interfaces of this family.

Ideally I think putting something in this section would be helpful:

A pair (host, port) is used for the AF_INET address family, where host is a string representing either a hostname in Internet domain notation like 'daring.cwi.nl' or an IPv4 address like '100.50.200.5', and port is an integer.

John, since you raised the issue, would you like to provide a doc PR?

New changeset 95dfb9c3aefdc981d23af700b753a6c97159ccad by Christian Heimes (johnthagen) in branch 'master':
bpo-33921: Clarify how to bind to all interfaces using socket (GH-7877)
https://github.com/python/cpython/commit/95dfb9c3aefdc981d23af700b753a6c97159ccad

New changeset 23355445625b8b41030dbda9decaf2f4aa7035a6 by Miss Islington (bot) in branch '3.7':
bpo-33921: Clarify how to bind to all interfaces using socket (GH-7877)
https://github.com/python/cpython/commit/23355445625b8b41030dbda9decaf2f4aa7035a6

New changeset 30f295b85ece2dc2b2b65018bd15090efa1de7dc by Miss Islington (bot) in branch '3.6':
bpo-33921: Clarify how to bind to all interfaces using socket (GH-7877)
https://github.com/python/cpython/commit/30f295b85ece2dc2b2b65018bd15090efa1de7dc